Technique
When You Need a Pointing Pair
Pointing pairs let information cross between a box and a line, which no earlier technique does. They are usually the deduction that unlocks a stalled medium or hard puzzle.
At a glance
Pointing Pair at a Glance
- Technique
- Pointing Pair
- Difficulty level
- Intermediate
- Also known as
- box-line reduction, locked candidate
- First needed on
- Medium puzzles
How to spot it
How to Spot a Pointing Pair
Choose a digit and a box, and mark every cell in the box where the digit is still possible. If they all sit in one row or one column, you have a pointing pair (or triple), and the digit can be cleared from that line elsewhere.
Common mistake
The Mistake Solvers Make
Running the logic backwards. If a digit's candidates within a row all fall inside one box, that is the mirrored case — eliminate the digit from the rest of that box, not the rest of the row.
Practice
Practise This Technique
Medium puzzles are where the pointing pair first becomes necessary. Generate a free printable medium Sudoku PDF and work through a few.
More techniques
Other Sudoku Techniques
- Naked Single — beginner
- Hidden Single — beginner
- Naked Pair — intermediate
- X-Wing — advanced
- Swordfish — advanced
FAQ
Pointing Pair — Frequently Asked Questions
What is a pointing pair in Sudoku?
A pointing pair occurs when all remaining candidates for a digit inside one 3×3 box fall in the same row or the same column. That digit must end up somewhere in that box, so it can be eliminated from the rest of that row or column outside the box.
How do you find a pointing pair?
Choose a digit and a box, and mark every cell in the box where the digit is still possible. If they all sit in one row or one column, you have a pointing pair (or triple), and the digit can be cleared from that line elsewhere.
Is the pointing pair a beginner or advanced technique?
It is an intermediate technique. Pointing pairs let information cross between a box and a line, which no earlier technique does. They are usually the deduction that unlocks a stalled medium or hard puzzle.